1. Field of the Invention
The present invention relates to fiber optic terminators, and more particularly to an angled fiber terminator.
2. Description of the Related Art
Optical fibers are used to transmit signals. Common fiber optic terminations/connectors terminate one fiber at a time. There are several connector styles (e.g., FC/PC, LC), but in all cases, a single fiber is inserted and glued in a precision ferrule, which is typically made of ceramic. The end of the ferrule and fiber are polished together to provide a smooth surface or a desired shape.
Angled fiber terminations and methods of making the same are provided in accordance with the present invention. In one embodiment, a structural system aligns and holds optical fibers in a substrate prior to a bonding process. When the fibers are glued in position and an optical face of the substrate is polished, the fiber termination will have one or more properties. For example, one property relates to an input/output point of each fiber (i.e., a polished face of the fiber core) that is located with a high degree of accuracy in the optical face of the substrate.
Another property relates to an optical axis of each fiber core that is positioned at a well-defined angle with respect to a surface normal of the polished face of the fiber and the optical face of the substrate. This property minimizes back-reflection and accurately defines the input/output angle of each fiber.
Another property relates to a plurality of fibers that are robustly supported by a structure, such that positional changes of their respective fiber bodies or xe2x80x98pigtailsxe2x80x99 will not cause changes in coupling efficiency, transmission loss, or damage to the fibers.
Another property relates to scalability of the assembly to support a fiber termination with a large number of fibers.
In one embodiment, kinematic supports may be implemented in a fiber termination, but a fiber should not be considered a rigid body. The body of a fiber engaged in an alignment assembly should be considered to have more than six independent degrees of freedom (DOF). Degrees of freedom beyond the normal six are deflected shapes that can be considered as normal modes of the fiber, i.e., an orthogonal set of elastically deflected states. One aspect of the present invention provides a support assembly that (1) supports the rigid body degrees of freedom, (2) controls the most dominant elastic modes, and (3) prevents non-negligible elastic modes.
One aspect relates to an optical fiber support assembly. The assembly comprises a substrate with a hole formed in the substrate. The hole comprises at least one noncircular opening. The hole is configured to receive a tip of a fiber such that an angle between an axis of the fiber tip and a normal of a surface of the substrate is greater than zero.
In one embodiment, the assembly comprises three structures. A first structure, such as a silicon substrate, locally controls the lateral positions of a plurality of fiber tips and an angle between an axis of each fiber tip and a normal of a surface of the first structure. A second structure, such as a locator plate, controls a lateral position of each fiber body behind the first structure. A third structure, such as a removable alignment fixture, may control a lateral position and a tilt of each fiber body at some location behind the second structure. A part of the assembly may then be bonded. In one embodiment, the bonding comprises filling a space defined by the first structure and the second structure with glue. The first structure, the second structure, and glue fill may control substantially all rigid body motion and all critical elastic modes of each fiber.
Another aspect of the invention relates to a method of supporting at least one optical fiber. The method comprises inserting a tip of the fiber into a hole in a first structure; and applying a load to a body of the fiber such that an axis of the fiber tip is at an angle with respect to a normal of a surface of the first structure.